The present disclosure generally relates to rock crushing equipment. More specifically, the present disclosure relates to a cone crusher including a bearing arrangement that allows for increased contact between the eccentric and lower head bushing during no-load conditions.
Rock crushing systems, such as those referred to as cone crushers, generally break apart rock, stone or other material in a crushing gap between two moving elements. For example, a conical rock crusher is comprised of a head assembly including a crushing head that gyrates about a vertical axis within a stationary bowl attached to a main frame of the rock crusher. The crushing head is assembled surrounding an eccentric that rotates about a fixed shaft to impart the gyrational motion of the crushing head which crushes rock, stone or other material in a crushing gap between the crushing head and the bowl. The eccentric can be driven by a variety of power drives, such as an attached gear, driven by a pinion and countershaft assembly, and a number of mechanical power sources, such as electrical motors or combustion engines.
The exterior of the conical crushing head is covered with a protective or wear-resistant mantle that engages the material that is being crushed, such as rock, stone, or minerals or other substances. The bowl which is mechanically fixed to the mainframe is fitted with a bowl liner. The bowl liner and bowl are stationary and spaced from the crushing head. The bowl liner provides an opposing surface from the mantle for crushing the material. The material is crushed in the crushing gap between the mantle and the bowl liner.
The gyrational motion of the crushing head with respect to the stationary bowl crushes, rock, stone or other material within the crushing gap. Generally, the rock, stone or other material is fed onto a feed plate that directs the material toward the crushing gap where the material is crushed as it travels through the crushing gap. The crushed material exits the cone crusher through the bottom of the crushing gap. The size of the crushing gap determines the maximum size of the crushed material that exist the crushing gap.
Cone crushers are generally designed to operate in a crushing mode where the crushing forces are supported by a bearing system. When the cone crusher is operated without rock or other material, referred to as no-load operation, the centrifugal forces created by the moving head assembly results in a completely different area of contact within the bearing system.
In addition to the no-load operating conditions, there are also instances in which the cone crusher is operated either with relatively small crushing forces due to a small quantity of rock entering the crushing chamber or with an offset load. During this reduced-load condition, the centrifugal forces of the head are greater than the crushing forces generated by crushing of the small quantity of feed rock. During the reduced-load condition, the bearing system will see a situation that can create uneven bearing alignment and may result in impact loading as the bushings are constantly realigned and misaligned by the changing rock forces.
During these no-load and reduced-load conditions, a loss of oil film between the bushing and the eccentric can be created. This loss of oil film can result in overheating or burning of the bushing during operation. This is a costly situation because the burning of the bushing and possibly other associated components may require the replacement of these components, resulting in the cost of the components, the cost of performing the unplanned maintenance and the lack of production resulting from the unavailability of the cone crusher.